The 'Cry Me Out' singer told BBC Radio 1 that she is a "massive fan" of soul legend Wonder and described their track as a "feel-good, throwback record". Wonder also plays the harmonica on the song.
"I've been such a massive fan [of Stevie Wonder] for so many years, it's crazy to actually see him in the flesh. I met his family and his wife, I spoke to him for a while and he's such a legend," she said.
Lott described the John Legend duet as "very vocal". She added: "I'm a massive fan of John Legend so I was really, really excited and happy about that."
Lott also revealed that her second album, to be released on November 7, will be more personal than her debut.
"I'm not afraid to use my personal experiences and put them into a song. I think that's when you get the best stuff anyway, when it's real emotion."
The singer had previously told Digital Spy that she had collaborated with big-name stars for the album. She premiered her brand new single 'All About Tonight' yesterday.
Listen to Pixie Lott's 'All About Tonight' below: